1. Field of Invention
The present invention relates to an underground pipeline repairing technology, and more particularly to a trenchless polymer grouting method for repairing a pipeline settlement by uplifting, wherein the pipeline settlement is caused by bad geological environments, such as soft soil layer.
2. Description of Related Arts
The underground pipeline belongs to the concealed engineering. Because of the complex and variable geological conditions in China, the construction of the underground pipeline always meets bad geological environments, such as the soft soil layer. With an improper treatment, the constructed underground pipeline is liable to settle, causing the misalignment and the leakage at the joints of the pipeline sections. Under the ground water pressure, the surrounding soil enters the pipeline through the gap, which leads to a clogging of the underground pipeline, affects the use of the pipeline and causes the inconvenience in the resident's lives. More seriously, the soil surrounding the leakage point continuously enters the sewage pipeline, causing a cavity outside the sewage pipeline. With time going by, the ground surface would crack and collapse, leading to the traffic jam and personnel casualties, and seriously threatening the safety of the buildings nearby. Thus, it is important to repair the settlement of the underground pipeline, so as to guarantee the normal lives and the life and property safety of the residents along the pipeline.
The conventional underground pipeline repairing is divided into the trench repairing with the pipeline replacement and the trenchless repairing. The trench repairing includes steps of: trenching the soil layer above the damaged pipeline; and, partially repairing the damaged pipeline or replacing the damaged pipeline with an intact pipeline. The trench repairing is able to effectively solve the settlement of the pipeline section. However, the trench repairing has a high construction cost and a long construction period; the trench repairing seriously disturbs the lives of the residents and the traffic in the construction area. Because of the crowded underground infrastructures, the ground greening areas, the building groups and the busy traffic in the city, only small space is left for the trench construction, so that it is almost impossible to repair and replace the damaged underground pipeline by the trench repairing. The trenchless repairing mainly includes the in-suit immobilization method, the insertion method, the pipe bursting method, the folded lining method and the spraying method. The in-situ immobilization method includes steps of: turning over an end of a flexible pipe which is soaked with resin; fixing the end of the flexible pipe at an inlet of the pipeline to be repaired; turning an inner surface of the flexible pipe which is soaked with the resin outward under a water pressure or an air pressure, in such a manner that the inner surface of the flexible pipe clings to an inner surface of the pipeline to be repaired; solidifying the resin to form an antiseptic and impermeable hard lining which clings to the inner surface of the pipeline to be repaired. The in-situ immobilization method has disadvantages of requiring special construction equipments and having a high requirement to the skill levels and experience of the workers. The insertion method includes steps of: dragging an intact pipeline directly into an old pipeline; and, grouting an annular gap between the old pipeline and the intact pipeline, so as to strengthen the connection between the old pipeline and the intact pipeline. The insertion method has disadvantages of highly decreasing a flow area of the old pipeline and requiring grouting after the construction is finished. The pipe bursting method includes steps of: crushing an old pipeline by a steel conical head at a front end of a pipe bursting device with a pneumatic hammer or a tractor; and moving with the conical head by a liner plastic pipe, so as to replace the old pipeline with the liner plastic pipe. The pipe bursting method needs to trench the ground to visually connect the liner plastic pipe. If the old pipeline has a serious misalignment, the liner plastic pipe for replacing would also have a serious misalignment. Moreover, the pipe bursting method needs to trench a starting working pit and a receiving working pit. The folded lining method adopts polyethylene (PE) or polyvinyl chloride (PVC) as a material of a pipeline, including steps of: changing a geometrical shape of the pipeline in a factory or at a construction site to decrease a cross-sectional area of the pipeline; pulling the pipeline having the cross-sectional area decreased into an old pipeline; and heating or pressurizing to recover an original size and an original shape of the pipeline, in such a manner that the pipeline, as a liner pipe, closely clings to the old pipeline. The folded lining method has a disadvantage of a potential structural damage to the pipeline during the construction, such as breaking and direction deviation. The spraying method is to spray cement mortar or an organic chemical grouting material onto an inner surface of an old pipeline to form a layer of film, so as to repair the old pipeline. The spraying method has disadvantages of a high requirement to the cleaning and the leakage stoppage of the pipeline, a long repairing time, a limited repairing, being time-consuming and manpower consuming and an unstable quality.
The above methods are able to solve the structural disease and the leakage of the underground pipeline to a certain degree. However, the above methods have more or less disadvantages of the high cost, the long construction period, the great difficulty in the construction, the uncontrollable construction quality and the necessity of the working pit during the construction. Moreover, the above methods are all unable to uplift and repair the settled pipeline section and reinforce the soft foundation. A secondary settlement may still happen to the repaired pipeline section, causing a secondary misalignment at the joints of the pipeline sections and accordingly the leakage and sand gushing. Because the conventional methods are unable to radically solve the problems of the gap and the leakage between the misaligned pipeline sections, due to the settlement of the underground pipeline, it is urgent to develop an underground pipeline settlement repairing technology which has a fast construction, a low impact on the environment and a low cost, and is practical and reliable.
The polymer grouting technology is a rapid foundation reinforcement technology developed in the 1970s. The polymer grouting technology injects a two-component polymer material to the foundation and makes use of the characteristic of the two-component polymer material that the material rapidly expands and solidifies after reacting, so as to reinforce the foundation, and fill the cavities or uplift the ground. The polymer materials have a light mass, a quick reaction, a good durability and good anti-seepage performance. Conventionally, the polymer grouting technology is mainly applied to the anti-seepage, reinforcement and repairing engineering of the large infrastructures, such as the roads, the tunnels and the dams. In order to satisfy the development requirements of the maintenance engineering and overcome the disadvantages of the conventional maintenance technology of the underground pipelines in China, the present invention combines the polymer bag grouting technology with the polymer pipe grouting technology, and provides a polymer bag grouting method for repairing the settlement of the underground pipeline, which is still not reported in China.